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Old 03-31-2007, 02:02 PM
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ksing44 ksing44 is offline
1995 E320 SE
 
Join Date: May 2002
Location: Downingtown, PA
Posts: 658
Give me some vacuum please

Quote:
Originally Posted by stevebfl View Post
based on your stated series of events I would first adjust the control pressure cable (bowden cable) to achieve earlier shifts! If that didn't achieve the desired effect I would turn the modulator in a turn.
Quote:
Originally Posted by stevebfl View Post
Idle speed is the lowest controlled speed. At that speed the throttle is basically closed, the piston's suck is greatest and thus one gets the highest vacuum. Actually one can achieve a higher vacuum by raising the engine speed to about 2000rpms and holding it. Anyway as the throttle opens the vacuum goes down. It would help here to use the absolute pressure description but dream of it as less suck because the restriction (throttle) is being removed.

Hi again Steve,

I’m back. When I first read your post, I thought you must have mistyped the thing about adjusting the Bowden cable to “achieve earlier shifts”. I thought you must have meant later shifts, like when I am accelerating hard and I don’t have the slip. Well, it looks like I was totally wrong! It still seems a bit counterintuitive to me, even after rereading your posts, but adjusting the Bowden cable to “achieve earlier shifts” seems to be helping to almost eliminate my shift flair.

I am going to reserve my final judgment until after I have driven for a while and made some more adjustments, but I really think I am on the right path now. As I said above, that is the path you originally recommended. Earlier shifts it is!

So right now the car shifts a little earlier going into 4th gear and it doesn’t seem to slip. I can’t help but think it may not slip partly because there really isn’t much force being applied to the trans at the lower speed and throttle, but based on rereading some of the things from your post, it is probably really because there is more vacuum at lower throttle, just as you explained. In addition, when I really stomp and go again there seems to be no flair. I suspect that is because even though the throttle is open there is still considerable vacuum from the higher engine speed. Am I making sense?

You know, I am having so much fun doing this myself I may have to try to find a way under my car to go after the vacuum modulator next. My car is a bit lower than normal, so there isn’t even enough room for your head to fit under my car. I don’t have jack stands or ramps or anything, but I think they may be in my future. I have read a little about stands, so I already understand that I should get the ones with pins that go right through the supports, as opposed to the scary ratchet things. I also liked the ramps I saw that had extended run-on areas that would hold the ramps in place with the weight of that car as you drive up and on. I guess the jack stands are nicer, since you then have better access to the wheels and tires, although ramps seem like a nice quick way to get the car up in the air.

Thanks again for your guidance!
Attached Thumbnails
Vacuum adjustments 1995 W124 E320-95-e320-se-front.jpg  
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I just couldn't give up on my 1995 E320.

I think it might be like always going back to that same bad relationship with an ex girlfriend.
You feel you love them too much, or you are just too stupid to know any better.



Flickr slideshow of my 1995 E320
http://www.flickr.com/photos/24145497@N06/sets/72157616572140057/

Last edited by ksing44; 03-31-2007 at 02:13 PM.
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